Problem with photos
I imported about 40 photos to place next to each other on the timeline. I did not use any transitions between them. When I deleted a couple, then moved the photos over to close the gap, I noticed that a brief flash of the previous photo is on the current photo. I can't get rid of this even if I delete the photos off the timeline and then put them back on.
Kevin Monahan commented
Try deleting render files in the Sequence menu.